This system offers rigid clamping and ultra precision locating that would be required in a precision manufacturing process. The clamping pressure will not pry or lift the alignment base as do other systems. The receiving surface is in clear view of the operator which makes the task of assuring perfect cleanliness an easier job to the system user. This cleanliness is a directly reflective of locating precision.
In U.S. Pat. No. 4,786,776 to Ramsbro, the design of a dovetail with a short dimension in height could be lifted from the table slightly during clamping. The clamping pressure could act as a pry which would cause this lifting action. This patent shows that it is possible to have machine dirt trapped down in the dovetail out of the clear view of the operator. This dirt could cause locating interference. Due to the extreme accuracy requirements that are commonly required by the type of manufacturing that would apply themselves to this kind of tooling system, for example wire electrical discharge machining, any location inaccuracies would place the results out of the commonly accepted parameters.
The present precision base and fixture adapter set-up system is designed with concern of clamping pressures that draw components together rather than components that may wedge and split the alignment surfaces. Also in this design, the height of the fixture assembly is kept to a minimum to help prevent possible interference during machining operations. This interference would cause the operator to have to move the guides of, for example a wire electrical discharge machine, farther apart. These guides support the cutting tool (the cutting wire) in the machine and the closer they can be kept to the workpiece, the easier it will be to achieve improved accuracy.
In the design of the base, care was taken in determining the material thickness required under the screw heads used, so that the base would be securely held to the machine surface. Also, by using a group of fastening screws to secure the base to the machine, holding pressure is increased and spread across a larger area of the tool. The base, which is heat treated and precision ground, provides for extreme accuracy and wear resistance resulting in long reliable service. With the locating surface of the base facing the operator the operator always has clear view of any dirt or interfering particles that could change the location of the adapters when the adapters are clamped to the base.
The base is designed with a main locating surface that will support and hold the adapter in perfect parallel with the table surface of the machine. The main locating surface is also of proper flatness to assure that a tilting effect does not occur when the mating surface of the adapter is clamped directly to the main locating surface of the base. A threaded mounting hole is provided in the main locating surface of the base and is set at a compound angle. This angle setting assists in the clamping of the adapter to the base. This clamping offers repeatability of the parts to be machined in the first axis or what is identified on the machine as the xe2x80x9cZxe2x80x9d axis.
A second surface, extending from the main locating surface of the base, acts as an alignment edge and contacts the adapter during the clamping process. This alignment edge will bring the adapter with the fixture mounted to it in perfect true with the second axis of the machine tool.
As the clamping pressure continues, the adapter then will come in contact with the third and final edge of the base. This contact surface identifies the final requirement of a complete location of three axis repeatability. This complete focus on assuring repeatability in all axes is the manner by which quality manufacturing can be performed with perfect duplication from part to part or set-up to set-up.
The design of this adapter is to allow the operator to mount a variety of fixtures to same. This flexibility the adapter offers enables an operator to hold fixtures for round parts, tall parts, thin parts, or even multiple parts. The adapters with the fixtures already mounted to them can be switched in and out of the machine tool with a minute of down time. This quick changeover makes an operation more profitable and flexible.